Devices and Methods of Measurements (E-Journal) / Приборы и методы измерений
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МЕТРОЛОГИЧЕСКИЕ ХАРАКТЕРИСТИКИ БОМБОВЫХ КАЛОРИМЕТРОВ В РЕАЛЬНЫХ УСЛОВИЯХ ЭКСПЛУАТАЦИИ
Get PDFThe high-usage measurement equipment for heat of combustion of organic fuels are bomb isoperibol calorimeters with a water thermostat. The stability of work of calorimeters at real conditions is important for maintenance of reliability of measurement results. The article purpose – the analysis of stability for parameters of calorimeters to environment changes. In this work influence room temperature (Тк) and heat exchange conditions on metrological characteristics of two models of calorimeters is considered with different degree of thermal protection: V-08МА and BIC 100. For calorimeters V-08МА the increase in a effective heat capacity (W) on 0,1 % by growth of Tк on everyone 5 °С is established. To use value W in all interval laboratory temperatures Tк = 14–28 °С it is necessary to correct W on 2,8 J/°C on everyone 1 °С changes of Tк. Updating W is required, if the correction exceeds error in determination W. For calorimeter BIC 100 it is not revealed dependences W from Tк. BIC 100 have constant-temperature cap, high stability a temperature in thermostat and stabilized heat exchange. It is established that an standard deviation of cooling constant for all calorimeters in direct proportional to standard deviation W.
СТЕНД ДЛЯ ОЦЕНКИ ТЕМПЕРАТУРЫ ПОВЕРХНОСТИ ФРАГМЕНТОВ ПРИРОДНЫХ СРЕД И ИХ ИМИТАТОРОВ
Get PDFResearch in the field of development of natural environments imitators that used for thermal cloaking of military machinery always connected with high material costs due to big sizes of cloaking objects. In this way we decided to create laboratory stand and methodic for obtaining data about temperature surface of fragments of natural environments and its imitators affected by the electromagnetic radiation of the optical wavelength range. We proposed to use a thermal imaging camera instead of the traditionally used spectrophotometric equipment for obtaining spectral characteristics of the objects under study affected by the optical radiation. This method allows us to evaluate the surface temperature of the object at different angles of lighting and viewing. Obtained data allows us to estimate the degree to which the imitator corresponds to a natural environment by the temperature and it’s dynamic of change.The construction of the stand allows to select angles of source of radiation and thermal detector in range 25–75 degrees from normal to the surface of object under study. The source of radiation consists of halogen lamps of MR16 type. The number of selected lamps and its power were chosen taking into account of imitation of intensity of sun radiation.The thermal camera MobIR M4 was used as infrared detecting unit in the range of 8–12 μm. This device has a matrix with a resolution of 160 × 120 pixels and its optical field of view, both vertically and horizontally is 25 to 19 degrees. Special remotely controlled device was created to automate the process of obtaining thermal images. Proposed methodic of measuring surface temperature of objects under study consists in obtaining thermal images at equal time intervals, their analysis using special software and plotting graphs. Thus we can use the developed laboratory stand and the methodic not only for temperature surface evaluation of fragments of natural environments but for its imitators.
ЦИФРОВОЙ ИЗМЕРИТЕЛЬ КОНТАКТНОЙ РАЗНОСТИ ПОТЕНЦИАЛОВ
Get PDFNowadays the technique of analog contact potential difference probes well developed. Due to the influence of various parasitic factors, analog probes has substantial errors. The integration time for automatic CPD compensation should be at least several seconds to achieve high accuracy measurements. The speed and the accuracy are essential, for example, for Scanning Kelvin Probes. The purpose of this paper is to develop a digital contact potential difference probe, with a higher accuracy and speed of measurements as compared to analog probe. The digital probe made on base of 32-bit microprocessor with a Cortex M4 core. Measuring cycle consists of at least two successive determinations of the output signal amplitude at different compensation voltage generated by the microcontroller. It allows synchronizing of the generated oscillations and reading of the measuring signals. Data arrays processed in real time of the Digital Signal Processing by microprocessor. In this case is possible computation of the root mean square value or determination of the desired spectral line of the signal after fast Fourier transformation. Both methods permit eliminate of random noise and spurious harmonics. The method provides the digital contact potential difference probe operation in large signal mode and with a large signal/noise ratio. This eliminates the error associated with the zero signal finding. Also the integration time for automatic CPD compensation of the measured value is not necessary, which significantly reduces the measurement time and eliminates errors of compensation and DAC. In addition, the microcontroller could control the movement of the probe during scanning and transfer data to the host computer on interface USB, etc
ИЗМЕРЕНИЯ АНТРОПОМЕТРИЧЕСКИХ ПАРАМЕТРОВ НА ОСНОВЕ ТЕХНОЛОГИИ ВИЗУАЛИЗАЦИИ ДВИЖЕНИЯ
Get PDFThe aim of this work was to estimate limitations related of the actual resolution of images taken into the object reconstruction procedure (using Structure from Motion method) applied for anthropometric measurements. This is necessary to define technical parameters of equipment used for this application. A series of 42 images of the sample static object were taken with use of high resolution camera. The object was in a stable position, properly illuminated with stable, diffused light sources. With use of VisualSFM software a virtual cloud of points representing real points of examined object was calculated. During tests a resolution of input images were changed then the calculation time and influence of the number of points in the cloud onto deviation of selected anthropometric parameters were analyzed. In conditions of the performed experiment decreasing of the resolution of input images to the level of 80 % of initial value (or lower) has significant influence onto results of the measurements of selected anthropometric parameters. Structure from Motion (SfM) technique can be adopted for anthropometric measurement systems when the input images are taken with high resolution imaging device (over a dozen of million pixels). Presented measurement method for anthropometry is characterized by ease of use, do not need any calibration before measurements or specialized equipment. Thank to this can be adopted in practice in any conditions and operated by unskilled operator.
ЭТАПЫ РАЗВИТИЯ И СОСТОЯНИЕ РАЗРАБОТОК ГРАВИТАЦИОННЫХ ГРАДИЕНТОМЕТРОВ ДЛЯ ПОДВИЖНЫХ ОБЪЕКТОВ. (Обзор)
Get PDFThe main steps of creating the gravity gradiometers for the measurement of inhomogineasly of gravitational fields on different mobile carriers, including in conditions of space, are considered on the basis of the analysis of the open literature. The role of these devices in modern science and technology is described. There are the basic physical principles which allowed to create devices that are actually used at the moment. The basic parameters of these devices characterizing their quality are also described. The aim of this study is to establish the basic problems that have to be solved to create these instruments, as well as obstacles to their widespread adoption in the various areas of science and technology and to formulate the basic tendencies and state of development at the moment. It is shown that the existing devices are too expensive, heavy and massive to be used widely on the Earth and in space. Here is described the desire of developers to create more simple, reliable and low-budget devices, which primarily intended for using in micro satellites is described here. It is concluded that the development of gravity gradiometer based on micromechanical and electromechanical technologies currently can not overcome the problems associated with noises inherent such instruments. This study in some ways is the rationale for the following work of authors, which sets out the principles of the new gravity gradiometer, which may help to solve some of the problems are described here
ОСОБЕННОСТИ ПРИМЕНЕНИЯ ПРОСТРАНСТВЕННЫХ КОНДУКТОМЕТРИЧЕСКИХ ДАТЧИКОВ ПРИ МОДЕЛИРОВАНИИ СМЕШЕНИЯ ПОТОКОВ ТЕПЛОНОСИТЕЛЯ В ЭЛЕМЕНТАХ ОБОРУДОВАНИЯ ЯДЕРНЫХ ЭНЕРГЕТИЧЕСКИХ УСТАНОВОК
Get PDFCoolant flow mixing processes with different temperatures and concentrations of diluted additives widely known in nuclear power units operation. In some cases these processes make essential impact on the resource and behavior of the nuclear unit during transient and emergency situations. The aim of the study was creation of measurement system and test facility to carry out basic tests and to embed spatial conductometry method in investigation practice of turbulent coolant flows. In the course of investigation measurement system with sensors and experimental facility was designed, several first tests were carried out. A special attention was dedicated to calibration and clarification of conductometry sensor application methodologies in studies of turbulent flow characteristics. Investigations involved method of electrically contrast tracer jet with concurrent flow in closed channel of round crosssection. The measurements include both averaged and unsteady realizations of measurement signal. Experimental data processing shows good agreement with other tests acquired from another measurement systems based on different physical principles. Calibration functions were acquired, methodical basis of spatial conductometry measurement system application was created. Gathered experience of spatial sensor application made it possible to formulate the principles of further investigation that involve large-scale models of nuclear unit equipment. Spatial wire-mesh sensors proved to be a perspective type of eddy resolving measurement devices
ПРИБОР ДЛЯ ИЗМЕРЕНИЯ ВРЕМЕНИ РЕЛАКСАЦИИ ПРОСВЕТЛЕННОГО СОСТОЯНИЯ ОПТИЧЕСКИХ МАТЕРИАЛОВ МЕТОДОМ «ВОЗБУЖДЕНИЕ-ЗОНДИРОВАНИЕ» В СУБМИКРОСЕКУНДНОМ ДИАПАЗОНЕ
Get PDFThe use of passive shutters to control the duration of the light pulses is an important aspect in the miniature and microchip lasers. One of the key spectroscopic characteristics which determine the properties of the material, which can be used as a passive shutter is relaxation time of its bleached state.We describe a device for determination of relaxation time of the bleached state in optical materials by the «pump-probe» method in the sub-μs time domain. This device allows one to determine relaxation times for materials which absorb at the light wavelength of 1.5 μm, e.g., materials doped with cobalt ions Co2+. The results of test examinations of the device are described, and the relaxation time of the bleached state of Co2+ ions is measured for a novel material – transparent glass-ceramics with Co2+:Ga2 O3 nanophase – amounting to 190 ± 6 ns. Применение пассивных затворов для управления длительностью импульсов оптического излучения является актуальной задачей в миниатюрных и микрочип лазерах. Одной из ключевых спектроскопических характеристик, определяющих свойства материала, который может быть использован в качестве пассивного затвора, является время релаксации его просветленного состояния. В статье описан прибор для измерения времени релаксации просветленного состояния оптических материалов методом «возбуждение-зондирование» в субмикросекундном временном диапазоне. Представлены его структура и характеристики. Прибор позволяет измерять времена релаксации просветления у материалов, поглощающих на длине волны 1,5 мкм, т.е., в частности, у сред, легированных ионами кобальта Co2+. Приведены результаты тестовых испытаний прибора, а также измерено время релаксации просветленного состояния нового материала – ситалла с кристаллической фазой Co2+:Ga2 O3 – оно составило 190 ± 6 нс.
СПЕКТРАЛЬНАЯ ФИЛЬТРАЦИЯ ИЗОБРАЖЕНИЙ ПОСРЕДСТВОМ ДИСПЕРСИОННЫХ СИСТЕМ
Get PDFInstruments for spectral filtration of images are an important element of the systems used in remote sensing, medical diagnostics, in-process measurements. The aim of this study is analysis of the functional features and characteristics of the proposed two image monochromator versions which are based on dispersive spectral filtering. The first is based on the use of a dispersive monochromator, where collimating and camera lenses form a telescopic system, the dispersive element of which is within the intermediate image plane. The second version is based on an imaging double monochromator with dispersion subtraction by back propagation. For the telescopic system version, the spectral and spatial resolutions are estimated, the latter being limited by aberrations and diffraction from the entrance slit. The device has been numerically simulated and prototyped. It is shown that for the spectral bandwidth 10 nm (visible spectral range), the aberration-limited spot size is from 10–20 μm at the image center to about 30 μm at the image periphery for the image size 23–27 mm. The monochromator with dispersion subtraction enables one to vary the spectral resolution (up to 1 nm and higher) by changing the intermediate slit width. But the distinctive feature is a significant change in the selected central wavelength over the image field. The considered designs of dispersive image monochromators look very promising due to the particular advantages over the systems based on tunable filters as regards the spectral resolution, fast tuning, and the spectral contrast. The monochromator based on a telescopic system has a simple design and a rather large image field but it also has a limited light throughput due to small aperture size. The monochromator with dispersion subtraction has higher light throughput, can provide high spectral resolution when recording a full data cube in a series of measuring acts for different dispersive element positions.
СОВЕРШЕНСТВОВАНИЕ ДЕЯТЕЛЬНОСТИ ИЗМЕРИТЕЛЬНЫХ (ИСПЫТАТЕЛЬНЫХ) ЛАБОРАТОРИЙ С ПОМОЩЬЮ СИСТЕМ МЕНЕДЖМЕНТА ЗНАНИЙ
Get PDFThe question of necessity of development and implementation of the Knowledge management system within the accredit measuring (testing) laboratory is being discussed. The conception offered is the methodlogy of expert system creation based upon ontologies for subjective areas of activities in the measuring (testing) laboratory, built on the base of process approach with the module principle. Рассмотрен вопрос необходимости разработки и внедрения систем менеджмента знаний в аккредитованной измерительной (испытательной) лаборатории. Предложена концепция методики создания экспертной системы на основе онтологий для предметных областей типа деятельность измерительной (испытательной) лаборатории, построенной на основе процессного подхода на модульном принципе